In a glasses-free 3D panel (a glasses-free three-dimensional display device), in which a light beam control element having linear optical apertures, such as cylindrical lenses or barriers (slits), arranged in a cyclic manner in the horizontal direction is disposed at the front of a display element, such as a liquid crystal panel, for enabling stereoscopic viewing with the unaided eye; the positional relationship between the display element and the light beam control element is of considerable significance. This positional relationship can be expressed using a panel parameter (a panel parameter related to the correspondence relationship between the display element and the light beam control element) that includes, for example, at least one of the following: the tilt of the light beam control element with respect to the display element; the pitch of an image corresponding to a single optical aperture; and the phase that indicates the amount of shift between the display element and the light beam control element. Then, based on the panel parameter, multi-view 3D images (called parallax images) is placed on the display element to thereby perform an appropriate stereoscopic display. However, it is rare that the parallax images are placed according to the design value, and more than a little error is present. In this regard, a technology called calibration is known in which the error is assessed and the correct panel parameter is estimated.
As a conventional calibration technology, a technology is known in which a parallel line group is displayed on, for example, a 3D panel and is observed from a predetermined position, and the following operations are repeated in a cyclic manner until the display reaches an optimal state: changing the panel parameter→performing display that reflects the change in the panel parameter→observation.
However, in the conventional technology, since the operations of changing the panel parameter→performing display that reflects the change in the panel parameter→observation need to be repeated in a cyclic manner; it requires a long period of time to perform calibration.